The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory captions and links exemplifying features within the Earth system. The community is invited to contribute digital imagery, short captions and relevant links.

Contrail Layers Over Maine

Not long after take-off from Boston, heading north on the evening of 24 April 2006, these interesting parallel contrails were observed somewhere over southern Maine. The photo was taken from a Boeing 777, looking west at an altitude of around 20,000 ft (about 6,100 m). In all, seven were counted -- until with perfect timing, an eighth entered into the frame (the narrowest trail at center to right center of photo). The lower contrails look like sutures in the sky. Wind shear is responsible for their zipper like effect. Because they're visible across the entire photo, it's obvious that at their altitude sufficient moisture was available to produce (and maintain) these lengthy streaks.